Using a function to generate a docstring in Clojure

Question

I want to be able to programatically define a docstring for one of my functions in clojure.

For example, I want to be able to do something like this:

(defn my-function
    (str "Here are some numbers " (range 10))
    []
    (println "This function does nothing right now."))

However, when I attempt to do this, I get "Parameter decleration str should be a vector". Is this just not possible in clojure or is there some sneaky way to do this? It would be useful to me to programatically generate parts of the docstring.

Answer 1

Yep, it's definitely possible. The thing you're running into here is that defn (or rather, the def special form that it expands to) attaches a docstring to the symbol iff the argument in second place is a string.

You can circumvent this by setting the :doc metadata yourself.

(defn ^{:doc (apply str "Here are some numbers " (range 10))} my-function
   []
   (println "This function does nothing right now."))

Or potentially by writing your own macro - but I think the above is the most straightforward way of doing it.